INTRODUCTION TO WHAT PCBs ARE:
· Ever wondered how Phones, Televisions, Laptops and many other electronics that we use in our daily lives have become more and more lighter, that’s because of constant advancement in technology also the usage of even tinier microscopic gadgets that are being made by engineers to further take the usage of electronics on another level.
· We all have a know how about certain microchips that are being worked up on upon to be even smaller but there are more to just microchips there’s a huge usage of PRINTED CIRCUIT BOARDS which have provided more ease to devices.
· PRINTED CIRCUIT BOARDS or PCBs are circuits that are made to fit many components in a single place on a circuit within a device.
· A PCB is made up of a glass fiber which is Copper coated placed on a circuit either mounted or etched.
· In the past when all the components like connectors, capacitors, insulators, resistors, microchips etc were all separately put into a device ,it didn’t provide a sleek design and didn’t give more space for a larger battery or a bigger camera with higher quality therefore to add more features and to provide more space in a device a PRINTED CIRCUIT BOARD was introduced.
· If we talk about something other than capacitors or resistors there’s wiring which are about 36 feet long that are fit in a mobile phones, they are also attached on a PCB ,this serves a provision of better connections of wirings, these wirings have Copper traces as the board is Copper plated due to this there’s a better supply of current which runs through the circuits.
· Professionally, the wirings are done on an angle of 45 degrees and are avoided on 90 degrees as it causes a hindrance in current supply.
· PCBs come in different sizes and in different types including SINGLE LAYERED PBCs in which only one side of the circuit is etched or mounted, DOUBLED LAYERED PCBs where both the sides of the circuit is designed and MULTI LAYERED CIRCUITS which mainly have more than 2 layers installed in them.
TYPES OF PCBs:
· Single layered PCBs
· Double layered PCBs
· Multilayered PCBs
· Rigid PCBs
· Flex PCBs
· Semi-flex PCBs
· Flex PCBs are the fastest growing interconnect solutions on the market due to advanced applications. These are found in almost all the compact electronic devices like cameras or mobile phones etc.
· Flex PCBs are made by using 3 materials :
1. Substrate material which is made up of costly polyamide film in some cases, this polyamide film provides a base for a flex circuit lamination.
2. Bonding adhesive which acts a bonding medium for creating the lamination, this bonding adhesive could also be a limiting factor as the medium could be temperature resistant.
3. Metal foils from which the circuits paths are etched.
· Metal foils come in various designs and thickness, widely and commonly used are Copper foils which provides a balance in the electrical and mechanical components of the circuit.
· The 3 layers could be stacked and can be forms as a multi-layered rigid PCB.
· Flex PCBs are normally used for dynamic flexing and static applications, they are best used when there’s a requirement bending the circuit into desired shapes.
· These circuits allow electrical engineers and designers to make smaller appliances while replacing the rigid boards to provide smaller designs with more space to add more new features.
· SEMI-FLEX PCBs:
· Semi Flex PCBs are made by depth milling technology.
· They are used when a static bond is needed.
· Semi-Flex PCBs as their name indicates are half flexible or they are half stiff, they are only moveable from specific points.
· They can pretty much save the same amount of space as Flex PCBs could, They are also quite reliable if they are manufactured correctly as if these circuits are installed the right way they could fit larger components in to smaller, confined spaces.
· Semi-Flex PCBs are also used when there’s a cost control as they are cheaper from Flex PCBs.
· Their Substrate molecule is cheaper than Flex PCB making them less costly than Flex PCBs.
· These circuits are achieved by reducing the thickness of FR4 material through controlled depth milling technology.
· Semi-Flex PCBs are well suited in the situations where a PCB must be bent during installation.
DIFFERNCES IN FLEX PCB AND SEMI-FLEX PCB:
· There are variety of factors that differs Flex PCBs to Semi-Flex PCBs:
1. Space available
2. Stress requirements
3. Thermal property
· Flex PCBs are built on flexible polymer film base.
· The entire board is flexible due to conducting material and a thin coating layer unlike Semi-flex PCBs.
· Flex PCBs could be bent and manipulated in any desired way as compared to Semi-Flex PCBs which do not possess this quality.
· Semi-Flex PCBs are used for cost control as compared to Flex PCBs they are cheap.
· Semi-Flex PCBs are used at pre-determinant ways at defined points.
· If the question arises in one’s mind about when and which PCB to use, if a work is being professionally done and there’s no need to worry about cost Flex PCBs may be used as they are made to bent just like you want them to.
· Both almost serves the same purpose but professionally Flex PCBs would be more reliable.